Rotary door closer with fluid check

ABSTRACT

1,227,248. Door closing device. OY WARTSILLA AB. 20 Aug., 1968 [21 Aug., 1967], No. 39682/68. Heading E2M. [Also in Division F2]  A fluid-braked door closing device has a piston 2 screw-threadedly engaged by a cylinder 1, the piston having a fluid chamber 4 which communicates with the cylinder via a non-return valve 8 and a return duct provided with an adjustable throttling means 13 which may be operated from outside the device. There is also a constant throttling means provided by an annular gap 10 between the piston and cylinder and an opening 11 in the piston wall. Movement of a door attached to the arm 7 causes rotation and thus axial displacement of the piston so that fluid flows from the chamber 4 to chamber 5 via valve 8. When the door is released, a spring 9 urges the cylinder I back to its initial position relative to the piston 2, fluid returning to the chamber 4 via ducts 12 and 11. The screw 13 may be made of a material having a greater coefficient of expansion than that of the piston so that the throttling effect and thus the closing speed of the door remains substantially unchanged with changes in temperature.

Dec. 22, 1970 "r. RASSA 3,548,443

ROTARY DOOR CLOSER WITH FLUID CHECK Filed Aug. 21, 1968 United States Patent ROTARY DOOR CLOSER WITH FLUID CHECK Toimi Rassa, Tampere, Finland, assignor to 0y Wartsila AB, Helsinki, Finland Filed Aug. 21, 1968, Ser. No. 754,211

Claims priority, application Finland, Aug. 21, 1967,

Int. Cl. E05 3/14 US. Cl. 16-52 7 Claims ABSTRACT OF THE DISCLOSURE A door closer comprises a fixed piston and a cylinder threada'bly engaged on the piston for rotation thereon. The cylinder is open upwards and receives the piston in its open part. There are turning arms connected to the cylinder for transmitting the turning movement of a door to the cylinder. The door closer is further provided with spring means acting on said cylinder to urge it into a position in which the door is closed, and a fluid system means between the piston and the cylinder to regulate the speed of the spring actuated closing movement of the door closer.

The invention relates to a spring actuated, fluid braked door closer, comprising a piston and a cylinder threaded on the piston for movement relative thereto.

Known door closers are usually rather large and heavy or they may be of a very simple construction braking the closing movement of the door only in the last phase of this movement. The object of the invention is to provide a continuously braking door closer of a compact and simple but still reliable construction.

The invention is characterized in that the cylinder of the door closer is open upwards and in its open part receives the piston, the cylinder being connected to turning arms transmitting the movement of the door in the form of a turning movement to the cylinder. By this means the turning arms can be attached to the lower part of the door closer and this makes it possible to obtain an advantageous construction. Due to the fact that the cylinder is the lower part and closed at its bottom, the door closer is leakproof and also easy to attach. A door closer according to the invention should preferably be attached to the door frame, but it may also be attached to the door.

In a preferred embodiment of the invention, a substantially closed fluid chamber is arranged inside the piston, and this fluid chamber is connected in a way known per se through a non-return valve to a compression chamber in the cylinder below the piston. From the compression chamber fluid is pressed back to the fluid chamber when the door is closed. In this embodiment of the invention the available space within the door closer is used very effectively, and this results in very small outer dimensions of the door closer.

In order to provide an adjustable closing speed of the door closer, a return duct with adjustable throttling is arranged between the compression chamber below the piston and the fluid chamber in the piston. The adjustable throttling may be obtained by means of a throttling screw attached at the upper part of the piston and turnable from the outside of the door closer. This construction makes it possible to obtain a throttling system which gives a practically constant closing speed at different temperatures.

Due to the fact that the viscosity of the fluid of a door closer usually is reduced with increasing temperature, the throttling in the return duct must increase with increasing temperature. This can be obtained by making the throttling screw for instance, of brass or any other material having a substantially higher thermal expansion than the material of the piston. This principle can be applied in throttling means of various consrtuetions.

In the following the invention will be more fully described with reference to the accompanying drawing the sole figure of which schematically shows an axial section of an embodiment of the invention.

In the drawing 1 indicates a cylinder, 2 a piston and 3 a thread engaging the piston to the cylinder, and providing axial movement between the piston and the cylinder when they are turned relatively each other. In the piston 2 there is a fluid chamber 4 and below the piston a compression chamber 5. The upper part of the piston 2 is formed as an attachment plate 6 which can be attached to the door frame. The cylinder 1 is provided with a turning arm 7 which in a manner known per se is connected to another turning arm (not shown) which in turn is attached to the door. When the door is opened, the cylinder 1 is turned by the turning arm 7. Turning of the cylinder also moves it downwards relative to the piston and this causes fluid to flow from the fluid chamber 4 through a non-return valve 8 to the compression chamber 5. When the door is left free the torsion spring 9 at the door closer urges the cylinder 1 back to its initial position relative to the piston 2, and this movement forces fluid to flow from the compression chamber 5 back to the fluid chamber 4. The returning fluid may entirely or partly be led through a constant throttling means formed by the slot between the piston and the cylinder and by an opening 11 in the piston wall. In the illustrated embodiment of the invetnion there is also a return duct 12 with an adjustable throttling. The throttling means of the return duct comprises a screw 13 which is threaded in the upper part of the piston and provided with a setting arm 14 extending along the upper part of the piston and operable at the edge of said upper part. By moving the setting arm 14 clockwise or counter-clockwise the throttling in the return duct 12 can be changed and in this way also the closing speed of the door closer. The movable parts of the door closer are enclosed in a casing 15.

In order to obtain a door closer unaffected by temperature, the screw 13 can be made of a material with a substantially greater thermal expansion than the piston 2. Upon increasing temperautre, the screw 13 will then expand more than the piston 2 and hence the throttling in the return duct 12 is increased without operation of the setting arm 14. The viscosity of the fluid in the door closer has decreased, however, due to the increased temperature and hence compensates the increased throttling whereby the closing speed of the door closer remains substantially unchanged.

The invention is not limited to the embodiment shown but modifications and variations thereof are feasible within the scope of the following claims.

What is claimed is:

1. A door closer comprising a piston, a cylinder threadably engaged on said piston for relative rotation thereon, said cylinder having a closed bottom and an open top, the piston extending within the cylinder through the open top thereof, turning arms connected to said cylinder for transmitting turning movement of a door as relative rotation between said piston and cylinder, spring means acting between said piston and cylinder to resist relative turning thereof by said turning arms and to urge the piston and cylinder to a relative rest position in which the door is closed, and fluid system means between said piston and cylinder to resist relative movement of said cylinder and said piston during return to said rest position.

2. A door closer as claimed in claim 1 wherein said piston includes means for attachment thereof, and thereby of the closer, to a fixed structure.

3. A door closer as claimed in claim 1 wherein said piston is hollow and defines a substantially closed fluid chamber, said fluid system means comprising a compression chamber provided in said cylinder below said piston and a non-return valve means connecting said fluid chamber with said compression chamber for allowing flow only in a direction from said fluid chamber to said compression chamber.

4. A door closer as claimed in claim 3 wherein said fluid system means further comprises a return duct with an adjustable throttling means in the bottom of said piston between said compression chamber and said fluid chamber.

5. A door closer as claimed in claim 4 in which said adjustable throttling means comprises a turnable throttling screw attached to said piston at the upper part thereof and operable from outside the door closer.

6. A door closer as claimed in claim 5 comprising a setting arm on said throttling screw extending along the door closer at the upper side thereof.

7. A door closer as claimed in claim 4 in which said adjustable throttling means comprises a throttling member having a higher coefficient of thermal expansion compared to said piston to produce increased throttling in said return duct due to increased temperature, said throttling member being threadably attached to said piston at a substantial distance from said return duct.

References Cited ERNEST R. PURSER, Primary Examiner I. A. CALVERT, Assistant Examiner US. Cl. X.R. 1657; 18889 

